A systematic review published in Genomic Press's journal Brain Medicine suggests that creatine monohydrate, a widely used muscle-building supplement, may help ease symptoms of major depressive disorder when taken alongside standard treatments. The findings matter because creatine is cheap, readily available and generally well tolerated, raising the possibility of an accessible add-on therapy, though the researchers stress the evidence is still preliminary and not grounds for changing clinical practice.

The Canada-based team analysed five randomised controlled trials, four looking at major depressive disorder and one at bipolar disorder with a depressive episode. Some studies showed benefit, such as women who took 5 grams daily alongside the antidepressant escitalopram, and others who added creatine to cognitive behavioural therapy. However, trials involving teenage girls found no benefit, and the bipolar study saw no significant improvement. Researchers note that people with mood disorders appear to process creatine differently in the brain, and because creatine aids energy production, disruptions may play a role in depression, though the link to mood "remains correlational". Lead author Bassam Jeryous Fares of the University of Ottawa called the signal "interesting, but not a verdict".